1. Field of the Invention
The present invention relates generally to latching devices, and more particularly to systems for latching hinged doors or panels and the like.
2. Background of the Invention
Various types of latching devices for fastening doors, panels and the like are known. Often the latching device is mounted in the door or panel near the edge so that the panel frame can be engaged to secure the panel.
Door-mounted "slam" latches employ a camming surface on the end of a sliding-bolt element which cooperates with a striker on the door frame or the frame itself to cause a bolt action to secure the door when it is closed against the frame. Such latches are activated to secure the door when the door is merely pushed shut or slammed. However, operation of the latch mechanism is required to release the latch to open the door. In some slam latches, the bolt is urged against a spring force by the action of a camming surface cooperating with the striker to slide into the latch housing as the door is being closed. The spring force then urges the bolt element to engage behind the door frame or to engage a keeper mounted on the door frame. In order to open the door, the bolt is manually operated to withdraw the bolt from engagement with the keeper so that the door can be swung open.
A prior art, flush-mounted slam latch includes a lockable metal lever or "paddle" for operating a latching pawl. The pivot-mounted lever moves in a plane perpendicular to the axis in which the latching pawl travels, and the lever and the latching pawl each include angled camming surfaces to transform the motion of the lever into the perpendicular travel of the latching pawl. Symmetric camming surfaces are provided on the latching pawl and the lever so that the latching pawl can be installed for either left side or right side operation. The key slot for the lock is located in through a hole in the lever so that the key used to unlock this latch must be removed from the lock cylinder in order for the lever to be lifted. The slam latch is operated by first pushing down the lever on one side of the pivot, and subsequently grasping the lever end extending above the surface of the panel on the other side of the pivot. Locking is accomplished through a thin metal ring mounted on the lock cylinder proximate the underside of the lever for rotation with the cylinder. A tab on the metal ring is adapted to engage a small bracket molded into the underside of the lever when the lock cylinder is in a "locked" position.
While such prior art latches can be adapted for use on either "left-handed" or "right-handed" panel doors, that is, panel doors which are hinged on either the right or left sides, there is a need for a slam latch which can be used on either type of door without modification. Further, there is a need for a lockable, flush-mounted slam latch which can be unlatched without removing the key after unlocking. There is also a need for a lockable, flush-mounted slam latch resistant to being "forced" by thieves or vandals. In addition, there is a need for a light weight, corrosion-resistant slam latch which can be used in adverse environments.